import type MarkdownIt from "markdown-it";
import type Renderer from "markdown-it/lib/renderer";

export default (md: MarkdownIt): void => {
  const renderToken: Renderer.RenderRule = (tokens, idx, options, env, self) => self.renderToken(tokens, idx, options);
  const defaultLinkOpenRenderer = md.renderer.rules.link_open || renderToken;
  const defaultLinkCloseRenderer = md.renderer.rules.link_close || renderToken;
  let isExternalLink = false;

  md.renderer.rules.link_open = (tokens, idx, options, env, self) => {
    const token = tokens[idx];
    const href = token.attrGet("href");

    if (href) {
      token.attrJoin("class", "vp-link");
      if (/^((ht|f)tps?):\/\/?/.test(href)) {
        isExternalLink = true;
      }
    }

    return defaultLinkOpenRenderer(tokens, idx, options, env, self);
  };

  md.renderer.rules.link_close = (tokens, idx, options, env, self) => {
    if (isExternalLink) {
      isExternalLink = false;
      return `<i-ri-external-link-line class="link-icon" />${self.renderToken(tokens, idx, options)}`;
    }

    return defaultLinkCloseRenderer(tokens, idx, options, env, self);
  };
};
